Water base lubricant containing dimethyl sulfoxide



WATER BASE LUBRICANT CONTAINING DIMETHYL SULFOXIDE Michael J. Furey,Berkeley Heights, NJ., assignor to Esso Research and EngineeringCompany, a corporation of Delaware No Drawing. Filed Oct. 26, 1956, Ser.No. 618,434

4 Claims. (Cl. 252-48.2)

This invention relates to water-base lubricants. Particularly, itrelates to a water-base lubricant wherein water has been thickened to alubricating oil viscosity with an organic thickener and small amounts ofan organic sulfoxide have been added to impart extreme pressureproperties to the lubricant.

The water-base lubricants of the invention are nonflamrnable,inexpensive lubricants having high load-carrying ability. Theselubricants may be used as cutting oils, hydraulic fluids, metal-workingfluids, and as general purpose lubricants where operating temperaturesare not excessive.

The lubricating compositions of this invention will comprise water whichhas been thickened to a lubricating oil viscosity with an ethercellulose and which contains an extreme pressure improving amount of adialkyl sulfoxide.

The ether cellulose thickeners operable in this invention include thewater soluble C to C alkyl cellulose ethers such as methyl cellulose,ethyl cellulose, propyl cellulose, butyl cellulose, etc., and whichinclude the monoand di-alkyl cellulose ethers, mixtures thereof, andmixed ether celluloses such as methyl ethyl cellulose, methyl propylcellulose, etc.

The dialkyl sulfoxides useful in the invention have the general formula:

wherein each R represents the same or different alkyl radicals,containing from 1 to 3 carbon atoms, i.e., methyl, ethyl and nandiso-propyl radicals. For example, the sulfoxide can be dimethylsulfoxide, diethyl sulfoxide, methyl ethyl sulfoxide, etc.

The lubricant of this invention will comprise a major proportion ofwater and a thickening amount, such as 0.5 to 10 wt. percent, e.g., 1 to5 wt. percent, of ether cellulose and an extreme pressure impartingamount of dialkyl sulfoxide, such as 0.5 to 5.0 wt. percent, e.g., 1.0to 3.0 wt. percent of the sulfoxide.

The invention will be further understood by the following examples.

EXAMPLE I A lubricant containing 1.7 wt. percent of a dimethyl ether ofcellulose (commercially available under the name of Methocel 400), 2 wt.percent of dimethyl sulfoxide and 96.3 wt. percent of water, wasprepared as follows: The Methocel 400 was mixed with about onefifth ofthe required amount of water as hot water for about minutes. Theremaining four-fifths of the water was then added as ice water and themixture was stirred until smooth and homogeneous. The resultant fluidwas clear and colorless. The viscosity of this base mixture at roomtemperature was approximately 260 centistokes,

States Patent ice . 2 which is similar in viscosity to an SAE 30 gradeoil. The 2 wt. percent of dimethyl sulfoxide was then added to themethyl cellulose thickened water. The sulfoxide immediately dissolvedand the resultant product remained clear and colorless.

The product of Example I was then evaluated for its load-carryingability in an Almen machine (a steel pin rotating at 600 r.p.m. betweentwo halves of a loaded bearing) with gradual loading at 10 secondintervals until failure. The product was also tested in the Shell 4-ballE.P. lubricant test. The results of these tests are shown in thefollowing table, along with comparative data for a typical minerallubricating oil.

Table 1 LOAD-CARRYING PROPERTIES OF METHYL CELLULOSE 'gIglENED WATERCONTAINING DIMETHYL SULF- As seen from the above table, the methylcellulose thickened water had very little load-carrying ability initself. However, upon the addition of 2 wt. percent of dimethylsulfoxide, it was able to carry a total of 15 Almen weights beforefailure, and carried a load of 102 kg. in the 4-ball E.P. test. Thetypical lubricating oil carried a maximum of only 3 Weights in the Almentest and a 45 kg. load in the 4-ball test, thus illustrating the veryhigh load-carrying ability of the water-base lubricant of the invention.

Other water-soluble additives may also be added to the composition, suchas dyes, corrosion-inhibitors, metal deactivators, wetting agents,supplementary anti-friction or anti-wear additives, and bacteriostaticagents.

What is claimed is:

l. A water-base lubricant composition comprising a major proportion ofwater, 1 to 5 wt. percent of a water soluble ether cellulose thickenerand l to 3 Wt. percent of a dialkyl sulfoxide having in the range of 1to 3 carbon atoms in each alkyl group, wherein said lubricantcomposition is a clear solution.

2. A water-base lubricant composition comprising about to 99 wt. percentwater, about 0.5 to 10.0 Wt. percent of a water soluble C to C alkylether cellulose thickener and about 0.5 to 5.0 wt. percent of awatersoluble dialkyl sulfoxide having in the range of 1 to 3 carbonatoms in each alkyl group, wherein said lubricant composition is a clearsolution.

3. A water-base lubricant composition according to claim 2 wherein saidether cellulose is a methyl cellulose and said dialkyl sulfoxide isdimethyl sulfoxide.

4. A process of lubricating relatively moving, contacting surfaces whichcomprises applying to said surfaces a lubricant consisting of waterthickened to a lubricating viscosity with a water-soluble alkylcellulose ether thickener, and containing about 0.5 to 5.0 wt. percentof a water-soluble dialkyl sulfoxide having in the range or 1 to 3carbonatoms in each alkyl group, wherein said lubricant is a clearsolution.

References Cited in the file of this patent UNITED STATES PATENTS 4 ModlNov. 14, 1944 Rogers et a1 June 28, 1949 Rogers et a1. .2; Dec. 12, 1950McBride Nov. 25, 1952 Sullivan et a1. Dec. 31, 1957 OTHER REFERENCESBastian: Metal Working Lubricants, McGraw-Hill, N.Y., 1951, pages 5 and6.

1. A WATER-BASE LUBRICANT COMPOSITION COMPRISING A MAJOR PROPORTION OFWATER, 1 TO 5 WT. PERCENT OF A WATER SOLUBLE ETHER CELLULOSE THICKENERAND 1 TO 3 WT. PERCENT OF A DIALKYL SULFOXIDE HAVING IN THE RANGE OF 1TO 3 CARBON ATOMS IN EACH ALKYL GROUP, WHEREIN SAID LUBRICANTCOMPOSITION IS A CLEAR SOLUTION.